The food industry uses flavor enhancers in a variety of savory products. These enhancers consist of monosodium glutamate (hereinafter MSG), hydrolyzed vegetable proteins, disodium salts of the 5′-nucleotides inosine monophosphate (IMP), guanosine monophosphate (GMP) and adenosine monophosphate (AMP), as well as autolysed yeasts. While all have disadvantages, the major enhancer, MSG, suffers from the problem known as Chinese Restaurant Syndrome.
The literature on taste enhancers is very large. A sample reference cited to show the various taste enhancers known is: S. Fuke and Y. Ueda, “Interactions between umami and other flavor characteristics”, in Trends in Food Science & Technology, Special Issue on Flavor Perception, December, 1996 (Vol. 7), Elsevier Sciences Ltd.
In the processing of tomatoes described in IL 107,999 w have obtained two fractions: serum and pulp where the serum is further concentrated: 
After removing from the tomato juice the pulp, the serum is concentrated to a value that is higher than 4.5° Bx which is the normal value of crushed tomatoes to reach a Bx value of 80 Bx. It can then be hydrolyzed (or hydrolyzed and then concentrated). This product is commonly referred to as Clear Tomato Concentrate (CTC)—although it is clear only when it is in the 4.5° Bx region while at higher Bx values it becomes opaque.